The document, under discussion for two years, is expected to examine ethical issues in biological research and health care that have emerged in recent years, including the cloning and freezing of human embryos, stem cell research and new therapeutic possibilities.

When members of the doctrinal congregation met in a plenary session last January, U.S. Cardinal William J. Levada, congregation prefect, said much of their discussion focused on the field of bioethics.

At that time, the cardinal hinted that a document was in the works. He said it might examine new therapeutic options and some ethical problems that were not explicitly considered by two previous church documents: the doctrinal congregation’s instruction “Donum Vitae” (“The Gift of Life”) in 1987 and Pope John Paul II’s encyclical, “Evangelium Vitae” (“The Gospel of Life”) in 1995.

Pope Benedict XVI was head of the doctrinal congregation when both those documents were published. Addressing the congregation in January, the pope said the new problems included the freezing of human embryos, the selective reduction of embryos, pre-implant diagnosis, research on embryonic stem cells and attempts at human cloning.

The pope said the starting point for the church’s reflection remains the same:

The two fundamental criteria for moral discernment in this field are unconditional respect for the human being as a person from the moment of conception to natural death, (and) respect for the originality of the transmission of human life through the acts proper to spouses.

The new document is expected to be unveiled at a Vatican press conference, the sources said.